1. Multiple Lewis Dot Structures
CO32-
24 total valence electrons 2- O C 2- O C 2- O C
Resonance structures
One of two or more Lewis structures for a molecule that cannot be depicted by a single structure

2. “Delocalized electrons” spread throughout the molecule.
Resonance Structures
Resonance
Structure
Resonance
Structure
Resonance
Structure
Experimentally, all three bonds are measured and have the same bond length...
...longer than a double bond and shorter than a single bond....
...i.e. the observed bonds have characteristics of both single and double bonds.
“Delocalized electrons” spread throughout the molecule.
Resonance Hybrid: Representation of the average resonance structures.

3. Resonance Structures: Benzene (C6H6)
Delocalized Electrons C H
Resonance Hybrid